Dielectric resonator oscillator and radar system using the same

Abstract

In the mass production of dielectric resonator oscillators (DROs), it is necessary to regulate the position where a dielectric resonator is placed with a high degree of accuracy and thus time required for the assembly work increases undesirably. Further, a terminating resistor and earthing means are formed at an end of a transmission line that is electromagnetically coupled to the dielectric resonator and constitutes the resonator on a dielectric substrate, and as a result the production cost increases. The present invention is characterized in that, in the components of a DOR, only a transmission line is formed on a dielectric substrate, and an oscillating active element and a terminating resistor and the earthing means on an MMIC chip are connected to the transmission line with metallic wires, metallic ribbons, or the like. Further, an open stub is formed in the middle of the transmission line on the side close to the oscillating active element when it is viewed from the dielectric resonator.

1. A dielectric resonator oscillator comprising:
 an MMIC; 
 a transmission line; and 
 a dielectric resonator disposed on a dielectric substrate, 
 wherein the MMIC comprises
 an oscillating circuit; 
 a frequency regulation circuit; and 
 a power supply circuit, 
 
 wherein an active element on the MMIC is connected to the transmission line with metallic wires or metallic ribbons, 
 wherein the dielectric resonator is electromagnetically coupled to the transmission line, 
 wherein the dielectric resonator oscillator further comprises a member for oscillating frequency regulation formed on the dielectric substrate, 
 wherein the member for oscillating frequency regulation comprises an open stub formed in the middle of the transmission line on the dielectric substrate on a side near to the active element when viewed from the dielectric resonator, 
 wherein an oscillating frequency of the dielectric resonator oscillator is regulated by a length of the open stub, and 
 wherein the open stub disposed in the transmission line on the dielectric substrate is formed opposite the dielectric resonator with the transmission line interposed therebetween. 
 
     
     
       2. The dielectric resonator oscillator according to  claim 1 ,
 wherein a terminating resistor and earthing means are formed on the MMIC, and 
 wherein an end of the transmission line is connected to the terminating resistor with metallic wires or metallic ribbons. 
 
     
     
       3. The dielectric resonator oscillator according to  claim 1 ,
 wherein a terminating resistor and earthing means are formed on a second MMIC other than the MMIC on the dielectric substrate or on a second dielectric substrate, and 
 wherein an end of the transmission line on the dielectric substrate is connected to the terminating resistor with metallic wires or metallic ribbons. 
 
     
     
       4. The dielectric resonator oscillator according to  claim 1 ,
 wherein the open stub is shaped so that a tip thereof opens toward the MMIC chip. 
 
     
     
       5. The dielectric resonator oscillator according to  claim 1 ,
 wherein the dielectric resonator oscillator comprises a negative resistance producing element that is formed on the dielectric substrate and connected to an oscillating active element on the MMIC with metallic wires or metallic ribbons, as the member for oscillating frequency regulation. 
 
     
     
       6. The dielectric resonator oscillator according to  claim 1 ,
 wherein the chip of the MMIC constituting the dielectric resonator is incorporated into a hole pierced in a dielectric layer that is the uppermost layer in a multilayer-structured dielectric substrate and bonded and fixed to an inner conductive layer of the multilayer-structured dielectric substrate, and 
 wherein the transmission line formed with a top conductive layer in the multilayer-structured dielectric substrate is connected to the surface of the chip of the MMIC with the metallic wires or the metallic ribbons on a substantially identical plane. 
 
     
     
       7. A dielectric resonator oscillator comprising:
 a transmission line formed on a dielectric substrate; and 
 an MMIC and a dielectric resonator disposed on the dielectric substrate, 
 wherein the MMIC comprises
 an oscillating circuit; 
 a frequency regulation circuit; and 
 a power supply circuit, 
 wherein an active element on the MMIC is connected to the transmission line with metallic wires or metallic ribbons, 
 
 wherein a permittivity of the dielectric substrate is smaller than a permittivity of the MMIC, 
 wherein the dielectric resonator is electromagnetically coupled to the transmission line by being disposed on the dielectric substrate in the vicinity of the transmission line or in the state of overlapping with the transmission line, 
 wherein a member for oscillating frequency regulation comprises an open stub formed in the middle of the transmission line on the dielectric substrate on a side near to the active element when viewed from the dielectric resonator, 
 wherein an oscillating frequency of the dielectric resonator oscillator is regulated by a length of the open stub, and 
 wherein the open stub disposed in the transmission line on the dielectric substrate is formed opposite the dielectric resonator with the transmission line interposed therebetween. 
 
     
     
       8. The dielectric resonator oscillator according to  claim 7 ,
 wherein the permittivity of the dielectric substrate is smaller than a quarter of the permittivity of the MMIC. 
 
     
     
       9. The dielectric resonator oscillator according to  claim 7 ,
 wherein the material of the dielectric substrate is alumina. 
 
     
     
       10. The dielectric resonator oscillator according to  claim 7 ,
 wherein a terminating resistor and earthing means are formed on the MMIC, and 
 wherein an end of the transmission line is connected to the terminating resistor with metallic wires or metallic ribbons. 
 
     
     
       11. The dielectric resonator oscillator according to  claim 7 ,
 wherein the dielectric resonator oscillator comprises a negative resistance producing element for oscillating frequency regulation that is formed on the dielectric substrate and connected to an oscillating active element on the MMIC with metallic wires or metallic ribbons. 
 
     
     
       12. The dielectric resonator oscillator according to  claim 7 ,
 wherein the chip of the MMIC constituting the dielectric resonator is incorporated into a hole pierced in a dielectric layer that is the uppermost layer in a multilayer-structured dielectric substrate and bonded and fixed to an inner conductive layer in the multilayer-structured dielectric substrate, and 
 wherein the transmission line formed with a top conductive layer in the multilayer-structured dielectric substrate is connected to the surface of the chip of the MMIC with the metallic wires or the metallic ribbons on a substantially identical plane. 
 
     
     
       13. A radar system comprising:
 a transmitting and receiving module; and 
 a transmitting and receiving antenna, 
 wherein the transmitting and receiving module comprises a dielectric resonator oscillator used as a signal source, 
 wherein the dielectric resonator oscillator comprises
 an MMIC; 
 a transmission line; and 
 a dielectric resonator formed on a dielectric substrate, 
 
 wherein the MMIC of the dielectric resonator oscillator comprises
 an oscillating circuit; 
 a frequency regulation circuit; and 
 a power supply circuit, 
 wherein an active element on the MMIC is connected to the transmission line with metallic wires or metallic ribbons, 
 wherein a permittivity of the dielectric substrate is smaller than a permittivity of the MMIC of the dielectric resonator oscillator, 
 wherein the dielectric resonator is electromagnetically coupled to the transmission line by being disposed on the dielectric substrate in the vicinity of the transmission line or in the state of overlapping with the transmission line, 
 wherein the dielectric resonator oscillator comprises a member for oscillating frequency regulation formed on the dielectric substrate, 
 wherein a terminating resistor and an earthing means are formed on the MMIC of the dielectric resonator oscillator, 
 wherein an end of the transmission line is connected to the terminating resistor with metallic wires or metallic ribbons, 
 
 wherein a member for oscillating frequency regulation comprises an open stub formed in the middle of the transmission line on the dielectric substrate on a side near to the active element when viewed from the dielectric resonator, 
 wherein an oscillating frequency of the dielectric resonator oscillator is regulated by a length of the open stub, and 
 wherein the open stub disposed in the transmission line on the dielectric substrate is formed opposite the dielectric resonator with the transmission line interposed therebetween. 
 
     
     
       14. The radar system according to  claim 13 ,
 wherein the dielectric substrate is made of LTCC, and 
 wherein the transmitting and receiving module comprises the dielectric resonator oscillator; a power amplifier MMIC to amplify transmitting signals; and two units of receivers MMICs to generate IF signals by mixing receiving signals with local signals. 
 
     
     
       15. The radar system according to  claim 14 ,
 wherein the open stub disposed in the transmission line on the dielectric substrate is shaped so that a tip thereof opens toward the MMIC chip of the dielectric resonator oscillator. 
 
     
     
       16. The radar system according to  claim 13 ,
 wherein the chip of the MMIC constituting the dielectric resonator is incorporated into a hole pierced in a dielectric layer that is the uppermost layer in a multilayer-structured dielectric substrate and bonded and fixed to an inner conductive layer in the multilayer-structured dielectric substrate, and 
 wherein the transmission line formed with a top conductive layer in the multilayer-structured dielectric substrate is connected to the surface of the chip of the MMIC with the metallic wires or the metallic ribbons on a substantially identical plane.